the vertex form of x²-x-6 is a(x-h)² + k
a=constant term, h & k are the coordinates of the vertex
thus
x²-x-6 = (x²-x +1/4) - 6 - 1/4
= (x-1/2)² - 25/4
so the coordinates of the vertex are 1/2, - 25/4
I just complete the square of ( x²-x ) by adding 1/4 and I minus back 1/4 to balance the equation
